The present invention relates to the control and actuation of the blades of an helicopter, and more particularly, to the independent control and adjustment of the blade cyclic pitch in response to the pilot's action and the helicopter forward speed.
Considerable efforts have been made to give this cyclic pitch variation a non-sinusoidal characteristic during helicopter forward flight when the craft velocity very seriously affects the nature of such cyclic pitch variations. More particularly two U.S. Patents address the subject: (1) No. 3,031,017 entitled CYCLIC PITCH CONTROL of Arcidiacono, and (2) No. 3,756,743 entitled ROTORS FOR ROTARY WINGED AIRCRAFT of Robertson. Both references identify the problem and offer solutions but, in both instances, fail to handle the problem of cyclic pitch variation requirement as a function of the craft forward velocity. My own referenced application did not treat that problem either.
However, the mechanical solutions which are presented therein for independently controlling blade collective and cyclic angles of attack lend themselves to the insertion of mechanisms which can easily introduce corrections to the cyclic pitch variations as a function of craft speed. Although an additional degree of complexity is also introduced thereby, the use of force amplifying systems eliminates the drawbacks therefrom. All components of the control and actuating system are enclosed inside a sealed housing, which fully protects these components.